Shuttle Brings Home A Scientific Payload

The shuttle Challenger and its Spacelab cargo glided to a smooth landing Monday in the Mojave Desert, returning home with priceless scientific data that will keep analysts busy for months.

The landing at 12:11 p.m. EDT on the dry lake bed at Edwards Air Force Base in California, which was shown on closed-circuit TV at Kennedy Space Center, appeared much softer than Discovery's landing at the center last

month.

Discovery blew a tire and ripped another as it stopped on the concrete runway.

Two squirrel monkeys and 24 rats aboard Spacelab were reported ''alive and well.'' They were moved to a waiting jet Monday afternoon and were to arrive at the space center Monday night, NASA officials said.

The rats will be decapitated so scientists can study how spaceflight affected their tissues. The monkeys won't be harmed, but will be studied before they are returned to NASA's Ames Research Center in California next week.

For scientists and NASA officials, the landing ended a weeklong mission that had a rocky start. Several of the 15 experiments malfunctioned and needed repairs, but eventually all but one provided reams of valuable data.

A wide-field camera was able to take only one exposure because Spacelab's outside air-lock door would not open.

''I would describe this as a fantastic mission,'' said Jesse Moore, NASA associate administrator for spaceflight. ''We're just delighted.''

Mission manager Joe Cremin said he would give the mission a grade of ''high B or low A.''

The Spacelab crew of seven men conducted experiments in atmospheric physics, astronomy, crystal growth, the reaction of liquid drops to zero gravity and life sciences.

Crewmen grew four crystals that are larger and appear more pure than anything that could be grown in Earth's gravity, and triggered new theories about the movements of liquids in weightlessness.

Other experiments captured spectacular photos of auroras and took millions of measurements about the upper atmosphere.

In all, the crew gathered enough information to fill 50,000 science books of 200 pages each. The data will take months to analyze and the results should be published within a year, space agency officials said.

Moore said NASA was particularly proud of completing two shuttle missions in 24 days, a boost for the agency's launch-a-month goal this year.

The crew members appeared fit when they left

Challenger about 40 minutes after touchdown. Waiting for them in crew quarters was ice cream with chocolate and cherries, a request they had made from orbit on Sunday.